Line a 13×9 inch pan with parchment or waxed paper. Spray with cooking spray

Freeze the cup of chocolate chips

Melt the butter in a medium sized saucepan over medium-low heat. Add in the mini marshmallows, reserving about a cup to add in later; stir constantly until the marshmallows melt and are nice and smooth

Remove from the heat and stir in the vanilla

Once combined, pour the marshmallow mixture over the Golden Grahams in a large mixing bowl and stir (working quickly) making sure all of the cereal is coated

Pour in the cup of chocolate chips and the reserved mini marshmallows

Scrape the mixture onto the prepared pan, spray your hands with a little cooking oil (to stop the mixture from sticking) and press down evenly